Hello Guys.I have three potentiometers(10K Linear) connected on Arduino Uno.I would like to ask how much current draw the three potentiometers?Do i need extrenal power supply?(maybe 5V 2A). I have upload a picture of my wiring diagram and the link with the potentiometers i use.Thank you.
Sorry but can you help me i am newbie.sorry again and thank you for your reply
Current equals voltage divided by resistance (Ohms law). There is 5V across each 10K resistance times 3 resistances. What do you calculate as the current?
5volt / 10000 ohm = 0.0005Amp, or 0.5mA (each pot).
1.5mA for three pots = nothing compared to the ~50mA draw of an Uno.
No extra supply needed.
Even after 2 years...i have also same question.
I think i understand his considerations.
If i am right ,he (and i) want to have potentiometers
as a replacements for some buttons.
Lets say we have a project with many sensors (and dont want pin expantion).
...and we are using all the digital pins.
And we need some buttons like
a)Button A -> roll menu
Then the idea is put a potentiometer in some analog port
and determine the current option selected by user according
optionCurrent=(Potentiometer * optionsLength)/1024;
Until here all good!
But after this ,,,coming the question....
0Oh...and i will be loosing power all the time?
So...i am making also this question (from this perspective)
...in case someone wants to kindly reply to beginners...
Am i loosing power (from baterry)
...................if i have a potensiometer instead of a button?
If yes then maybe the idea is not so good idea !
Thank you in advance.
P.S. My multi meter is too inexpensive...to measure..
...and i am still beginner !!!!
Which Arduino do you have, and which part of the answers don't you understand.
An Uno (assuming) by itself draws about 50mA, so is not really the right board for battery power.
Adding a 10k potentiometer draws 1% more current (5/10k= 0.5mA).
A button draws zero current when not pressed.
So why use a pot.
Ok..first of all thank you for your immidiate reply.
I have uno but this question is for general understanding ...so it does not matter.
(I know also that without usb ,regulators need less power)
(and i know that the lesson is also for electicity and not strict for potentiometer and arduino)
(but arduino is for beginners!!!)
Ok...so because i am too old to go to school i am asking a little more explanation.
(if you or someone have time )
And ok ,,,i understand your point that (finally) i am learning that
no need to use a potensiometer instead of a button ..
But i really like to learn how much Amperes i am loosing in BOTH cases
of a potentiometer.(Open-Closed)
So...from Uno Specs we have this
DC Current per I/O Pin 20 mA
DC Current for 3.3V Pin 50 mA
But lets take that 50 mA that you say.
When the potensiometer is totally Close 10 k ( full resistor-right)
then ok... 5 volt /10.000 =0.5 mA
This is the part i can understand.
But what happening in the case that potentiometer is Open (left)
and the resistance is ZERO kilo -ohms ?
The equation will give positive infinity...+00
PS.Be patient to children!!(and again thank you)
The pot is usually wired from Vcc to ground with the wiper going to an analog input. There are 2 paths for current flow. Across the pot and through the wiper into the input. The current across the pot (Vcc to ground) is V/R (Ohm's law). The resistance from Vcc to ground is constant. So a 10K pot will pass 0.5mA, constantly.
An analog input's input impedance is much greater than 1M, so that will pass much less than 1uA (virtually zero). The current through the pot does not change with wiper position.
Hmmm!! ..i think now i got it.
Its like to have a constant resistor from Vcc to Grnd
and as so ...the equation I=V/R will be applied.
And JUST that the potentiometer will give the Voltage signal
depending on where we have the niddle-position
Thank you all !
PS Never use potensiometer for "silly things!"heheh